Many patients suffer from occluded arteries and other blood vessels which restrict blood flow. Occlusions can be partial occlusions that reduce blood flow through the occluded portion of a blood vessel or total occlusions (e.g., chronic total occlusions) that substantially block blood flow through the occluded blood vessel. Revascularization techniques include using a variety of devices to pass through the occlusion to create or enlarge an opening through the occlusion. Atherectomy is one technique in which a catheter having a rotatable cutting element thereon is advanced through the occlusion to form or enlarge a pathway through the occlusion. Typically, a guidewire is initially placed across the occlusion and then the atherectomy catheter is advanced over the guidewire as the atherectomy catheter is passed through the occlusion. However, in some instances in which there is an insufficient lumen through which to pass the guidewire, such as a chronic total occlusion (CTO), it may be difficult or impossible to position a guidewire across the occlusion for the atherectomy catheter to follow when the cutting element engages the occlusion.
Therefore, a need remains for alternative ways to penetrate and traverse occlusions, such as chronic total occlusions, to form or enlarge a pathway through the occlusion to improve blood flow through the blood vessel.